Welding machine for pin spotting



Original Filed Dec. 6, 1963 D 21', 1970' D.IM. GLENDENNING 3,508,025

WELDING MACHINE FOR PIN SPOTTING 2 Sheets-Shet 1 53- 5| 53 INVENTOR oonM. GLENDENNING 54 55 0 so F|G.3 b m w ATTORNEYS April 21, 1970 D. M.GLENDENNING WELDING MACHINE FOR PIN SPOTTING 2 Sheets-Sheet 3 OriginalFiled Dec. 6, 1963 I HOLD CRC STO P E T3 .L 51. 711

/LS-l CRc ETS G N N n OD T N m5 VL G M 0 D United States Patent US. Cl.219-51 7 Claims ABSTRACT OF THE DISCLOSURE An apparatus for assemblingchain having pintle pins including welding heads and .timer cyclecontrols for welding each pintle pin to the legs of its link as thechain is indexed past the welding heads.

This invention relates to link chains and particularly to an improvedapparatus for acting on link chains to ensure longer life thereof underadverse conditions.

This is a division of application Ser.'No. 328,650, filed Dec. 6, 1963,now Patent No. 3,325,991.

Link chains are generally made up of a succession of identical linksthat are hinged together by pintle pins. The links of such chainsusually include spaced parallel legs having at one end a tubular bearingportion adapted to receive a pintle pin. The ends of the legs oppositethose having .the tubular bearing portion are offset a greater distancethan the ends having the bearing portion, and

these offset ends have aligned pintle receiving holes extendingtherethrough for the reception of the pintle pin within the tubularbearing portion of the next adjacent link.

When the chain is in use, the tubular bearing portion provides thepivotal action between links, and the offset ends must be restrainedfrom oscillating on the pintle pins because ,the unit pressure at theseoffset ends causes excess wear, lengthening of the chain and effectingits ultimate destruction.

Although many types of connections between the pintle pins and theoffset ends of the links are currently employed to prevent oscillatorymotion between them, during severe use these connections often becomeloose, permitting oscillatory motion effecting excessive wear,lengthening of the chain and the shortening of its life.

That principal object of the invention is to providean apparatus forhandling assembled chain which may be provided with or withoutoscillation restraining means between the pintles and the offset legs,and for acting on .the chain in a manner to permanently preventoscillation of the offset ends of chain links on their pintle pins.Another object of the invention is to provide such a machine thatindexes the chain links past aligned spot welding heads for spot weldingthe offset link ends .to their pintle pins. Y

Still another object of the invention is to provide such a machine inwhich means is provided for indexing the assembled chain past alignedwelding heads arranged transversely to the path of travel of theassembled chain. Still another object of the invention is to providesuch a machine which is provided with restraining means for maintainingthe chain taut as it passes .the welding heads Another object of theinvention is to provide. such a machine in which the chain is maintainedin positive en-' gagement with a conducting plate while the chain passesthe welding heads.

In one aspect of the invention, a frame may include a horizontal tabletop having a sprocket at one end that is connected to a friction brakemeans to restrain its motion to a predetermined extent. At the other endof the table 3,508,025 Patented Apr. 21, 1970 top, another sprocket maybe located in longitudinal alignment with the first sprocket, and bothmay be mounted such that their pitch circles are substantially tangentto the table top, so that with a chain riding over and in drivingengagement with both sprockets, the portion of the chain betweensprockets rests in contact with the table top.

In another aspect of the invention, a ratchet wheel may be fixed to thesprocket not connected to the brake, and a pawl attached to a pivotallever may be arranged .to cooperate with the sprocket so as to index itstep-by-step when the pawl means is oscillated.

In still another aspect of the invention, the end of the lever oppositethat supporting the pawl means may be connected to a rod attached to apiston within a cylinder mounted on the frame. The arrangement is suchthat the admission of pressure fluid to one end of the cylinder (aspring may be used in the other end) while exhausting the opposite endcauses the pawl means to be indexed and the chain to be given astep-by-step movement over the table .top.

In still another aspect of the invention, a section of the 'table topmay be electrically conductive, providing an electrical ground, againstwhich the chain is maintained in an electrically conducting manner by anidle sprocket pivotally mounted on the table top in such fashion that itis caused to mesh with the chain as it passes over the conductingportion of the table top.

In still another aspect of the invention, the table top may supportwelding head supports on each side of the path of travel of the chain,and they may be arranged for horizontal movement transversely of thechain path as well as vertically. Each support is adapted to have fixedto ita welding head which may include its own reel of welding rod thatis fed through the welding head to its active end which, through theadjustment of .the support, can be located in close proximity to thechain as it is indexed along its path of travel.

In still another aspect of the invention, a control circult may beprovided for successively indexing the chain past the welding heads suchthat each pintle pin stops adjacent the transversely disposed weldingheads; the welding rod is fed into contact with the pintle heads andlinks to thereby effect a Weld between the two.

The above, other objects and novel features of the invention will becomeapparent from the following description and accompanying drawings whichare merely exemplary.

' In the drawings:

FIG. 1 is a plan view of a machine to which the principles of theinvention have been applied;

FIG. 2 is an enlarged end elevation of a the chain being treated in FIG.1;

FIG. 3 is a plan view of the chain of FIG. 2;

FIG. 4 is a sectional view taken substantially along line 44 of FIG. 1;and

FIG. 5 is a wiring diagram for the machine shown in portion of FIG. 1.

Referring to the drawings, and particularly toFIGS. 1 and 4, theprinciples of the invention are shown as applied-to a machine includinga table top 10 supported by legs 11. A sprocket 12 may be fixed to ashaft 13 at one end of the table top 10. The shaft 13 may have mountedon it a friction-producing device 14 arranged to provide a drag on chain15 that is pulled along table top 10, as will be described later. Thelocation of sprocket 12 is such that its major portion lies beneathtable top 10, and its pitch circle is substantially tangent to the tabletop 10 so that the driving portion of its teeth are above the table topand capable of meshing with the links the table top 10.

A driving sprocket 16 may be mounted on a shaft 17 journaled in abracket 18 on table top at the end thereof opposite the end where thesprocket 12 is mounted. The sprockets 16 and 12 lie in the same verticalplane, extending longitudinally of table top 10, and the sprocket 16 isalso mounted such that a major portion thereof is below table top 10 andwith its pitch circle substantially tangent to the table top 10.

The end of shaft 17 opposite that to which sprocket 16 is connected mayhave a ratchet wheel 19 fixed to it adjacent a lever 20 that isjournaled for oscillation on shaft 17 and supports a pawl 21 forcooperation with the ratchet wheel 19. The lower end of lever 20 isconnected to a rod 21' that is connected through a turnbuckle 22 to apiston rod 23. The piston rod 23 extends into a cylinder 24 and supportsa piston therein. Admitting pressure fluid to the one end of cylinder 24While exhausting the opposite end (a spring may be used in the oppositeend of the cylinder) oscillates lever 20 and hence indexes sprocket 16together with chain in a step-by-step fashion. By adjusting theturnbuckle 22, it is possible to adjust the extent of indexing movementof chain 15 for a purpose to be described later.

The table top 10 may be made up of a machinery steel sub-base structure25 on top of which hardened and ground stock 26 may be mounted forsupporting the chain 15. A recess may be formed in the hardened andground stock within which may be located a hardened brass insert 27,providing a highly electrically conducting portion of the top 10.

Chain 15 may be held in firm contact with the brass insert 27 as it isindexed along the table top 10 by an idler guide sprocket 28 mounted forrotation at the end of an arm 29 mounted for pivotal movement on a shaft30. The weight of the sprocket 28 and arm 29 maintains electricalcontact between chain 15 and brass insert 27, and sprocket 28 accuratelyguides the chain 15 in its path of travel across insert 27 for a purposeto be described later.

Identical adjustable welding heads and supports therefor are mounted intransverse alignment on table top 10 on each side of the chain 15. Sincethey are identical,

only one will be specifically described. Thus, a bracket 31 may includea member 32 having ways 33 within which may be mounted an element 34 forvertical sliding motion. The element 34 may have a nut portion 35 thathas a rotatable but non-axially movable screw 36 threaded thereinto. Acrank 37 may be fixed to screw 36 for rotating it in either directionand hence vertically moving element 34 in either direction.

The element 34 may extend toward the sprocket 28 and may include amember 38 at right angles to the member 32 on bracket 31. Member 38 mayalso support a rotatable, non-axially movable screw 39 that threads intoa nut 40 integral with a slide 41 that rides in ways 42 on member 38. Acrank 43 may be fixed to screw 39 so that its rotation in bothdirections causes reciprocation of slide 41 along ways 42.

A Welding head '44 may be mounted on the slide 41. It may be acommercial item such, for example, as one sold by the A. O. SmithCompany under the trade name Blitz-Matic are spot button welder. It maycomprise a reel 45 mounted on an arm 46 for feeding welding rod 47through the head to an electrode element 48.

There is an identical welding head mounted on an identical slide 41 ofan adjustable supporting means on the opposite side of the chain 15 andin transverse alignment. By turning the cranks 37 and 43 for eachmounting means, the electrode element 48 of each welding head can beaccurately located on each side of chain 15 in alignment with a pintlepin of one of the chain links. Then, by adjusting the turnbuckle 22, thechain 15 can be indexed in a step-by-step fashion so that each pintlepin becomes located in line with the electrode elements 48. The guidesprocket 28 maintains accurate positioning of the links of the chain 15as they are indexed into position relative to electrode elements 48.

'Referring to FIGS. 2 and 3, each link of chain 15 may comprise legs 49and 50 joined at their one ends by a tubular bearing portion 51 that isin alignment with holes 52 for receiving a pintle pin 53. The oppositeend of legs 49, 50 may be offset so that the distance between them issuch as to slidingly receive the non-offset leg end of the next adjacentlink. Holes 54 may be provided in the offset ends and may be aligned forreceiving the pintle pin 53. The holes 54 may include a key-shapedrecess 55 therein for receiving metal of the pin 53 when the latter isstaked. After the staking operation, the remainder of the metal of thepintle pin beyond the offset links may be spun in the usual manner. Thepreviously described operations of staking and spinning may be performedin the production line and the assembled chain fed over table top 10 aspreviously described. The electrode elements 48 may be adjusted to be inalignment opposite the filled key-shaped recesses 55, and as each indextakes place, the next succeeding pintle pin moves into position betweennozzles 48. Also, as the welding rod is fed forwardly, contacting thepintle pin, a button weld is performed which ensures permanentnon-loosening of the pintle pin 53 in the holes 54 of the offset ends ofthe legs of each link of chain 15. By welding opposite the recess, uponcooling, there will be a tight joint between the loaded side of the pinand the aperture.

Referring to FIG. 5, closing of control contacts 56 with operatingswitch 57 in the position shown and closing of push button contacts 58energize CRB relay, closing CRB-1 holding contacts and CRB-2 contacts.Normally, the spring within the cylinder 24 maintains lever 20 in itsdotted line position, closing LS-l contacts (FIG. 4). Accordingly,turning switch 56 to on energizes CRC relay through the closed contactsLSFI, thereby closing holding contacts CRC-l as well as closing CRC-2contacts. Closing the CRC-2 contacts with contacts CRB-2 closed aspreviously described, energizes a solenoid 59 that operates a valve toadmit pressure fluid to cylinder 24 to move lever 20 to its solid lineposition and thus index chain 15 so that the pintle pin of its nextsucceeding link moves into alignment with electrode elements 48.

Movement of lever 20 to its solid line position closes contacts LS-2,thereby energizing TDR relay as well as an electronic timer ET-3 for apurpose to be described later. After a predetermined time interval, timedelay contacts (not shown) close which energizes the circuitry for thewelding heads 44 which latter are commercial items and per se form nopart of this invention. The circuitry for these welding heads includeselectronic timers that control the duration of the cycle of operationincluding, among other things, the feeding of the welding rod throughelectrode elements 48, the control of a C0 gas envelope about the weld,and the control of the water cooling of the heads. The electronic timerET-3 is set to open contacts ET-3 after the welding operation has beencompleted, de-energizing relay CRC, opening contacts CRC-2, therebyde-energizing index solenoid 59 permitting the spring in cylinder 24 toreturn lever 20 to its dotted line position, thus opening contacts LS2and closing contacts -LS1. Opening contacts LS-2 de-energizes TDR relayas well as ET3 relay, the latter closing contacts ET-3 so that withvcontacts LS-1 again closed, a new cycle is initiated.

Although the various features of the improved machine for treating chainlinks has been shown and described in detail to fully disclose oneembodiment of the invention, it will be evident that changes may be madein such details and certain features may be used without others withoutdeparting from the principles of the invention. 1

What is claimed is:

1. Apparatus comprising in combination, a horizontal support; means onsaid support for indexing a section of link chain thereover; weldingheads including electrode elements mounted on said support on each sideof said chain; means for adjusting said welding heads so that saidelectrode elements can be located accurately at predetermined pointsrelative to pintle pins of said chain; time cycle control means forcausing said apparatus to weld each pintle pin to the legs of itscorresponding link as said chain is indexed past said welding heads; andmeans for accurately guiding said chain as it passes between saidwelding heads and said support having means forming a part thereof andhaving in cooperation with said guiding means a high electricalconductivity.

2. The apparatus of claim 1 wherein there are sprocket means pivotallymounted on said support in position to mesh with said chain, forcing itinto intimate contact with said means forming part of said support whichhas high electrical conductivity.

3. Apparatus comprising in combination, a horizontal support; alignedsprockets mounted at each end of said support with their pitch circlessubstantially tangential to the top of said support; means for applyinga dragging action to one sprocket; means for indexing the othersprocket, whereby a length of link chain meshing with and extendingalong said support is indexed in a step-bystep fashion; welding headsincluding electrode elements arranged on each side of said chain on saidsupport; means for adjusting said Welding heads so that said electrodeelements can be located at predetermined points relative to said chain;and timer cycle control means for causing said apparatus to weld eachpintle pin to the legs of its corresponding link as said chain isindexed past said welding heads.

4. The apparatus of claim 3 wherein there are means for accuratelyguiding said chain as it passes between said Welding heads and there aremeans forming part of said support which in cooperation with saidguiding means has a high electrical conductivity.

5. The apparatus of claim 4 wherein there are sprocket means pivotallymounted on said support in position to mesh with said chain to force itinto intimate contact with said highly conductive portion.

6. The apparatus of claim 3 wherein there are means to apply a draggingaction to one sprocket, there is a pawl and ratchet means connected tothe other sprocket with a section of link chain extending between andmeshing with the sprockets, and there is a pressure fluid means foroperating said pawl and ratchet means to index the chain along saidsupport.

7. Apparatus comprising in combination, a horizontal support; alignedsprockets mounted at each end of said support with their pitch circlessubstantially tangential to the top of said support; means for applyinga dragging action to one sprocket; pawl and ratchet means connected tosaid other sprocket; a section of link chain extending between andmeshing with said sprockets; pressure fluid means for operating saidpawl and ratchet means to index said chain along said support; weldingheads including electrode elements arranged on each side of said chainon said support; means for adjusting said welding heads so that saidelectrode elements can be located at predetermined points relative tosaid chain; means for accurately guiding said chain as it passes betweensaid welding heads; means forming part of said support in cooperation.with said guiding means having a high electrical conductivity; andtimer cycle control means for causing said apparatus to weld each pintlepin to the legs of its corresponding link as said chain is indexed pastsaid welding heads.

References Cited UNITED STATES PATENTS 1,873,619 8/1932 Mojonnier 2191,907,092 5/1933 Reyburn 59-31 2,319,979 5/1943 Collins et al. 74-252RALPH F. STAUBLY, Primary Examiner B. A. STEIN, Assistant Examiner

